Rust inhibiting composition



United States Patent 3,458,444 RUST INHIBITING COMPOSITION William T. Shepherd, Port Arthur, Howard J. Platte, Groves, and Federico P. Gonzalez, Nederland, Tex., assignors to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 17, 1967, Ser. No. 683,774 Int. Cl. Clllm 1/32; C23f 11/14 U.S. Cl. 252-51.5 Claims ABSTRACT OF THE DISCLOSURE Rust and sludge inhibiting additive for mineral lubricating oils comprising the reaction product of an alkenyl succinic acid or anhydride and a tertiary amine represented by the formula RN(R'OH) in which R is an aryl or alkaryl radical and R is a divalent alkylene radical having from 2 to 4 carbon atoms and mineral lubricating oil composition containing said rust and sludge inhibitor.

This invention relates to a novel rust inhibiting composition formed by the reaction of an alkenyl succinic acid and/or anhydride with an alkanolamine and to a turbine lubricating oil composition containing the rust inhibitor.

Alkenyl succinic acids and anhydrides have heretofore been reacted with aliphatic amines and with certain alkanolamines in conjunction with aliphatic acids to produce reaction products exhibiting rust inhibiting properties, see US. 2,540,800 and U.S. 2,638,449. The level of rust inhibition imparted by these materials, however, has not been entirely satisfactory. In addition, some of the known reaction products have been ineffective for preventing the formation of sludge when employed in a turbine lubricating oil composition. In contrast to the known rust inhibitors, the reaction product of the present invention is highly elfective as a rust inhibitor in the ASTM Turbine Oil Oxidation Test (D-943) and, surprisingly, also for reducing or substantially preventing the formation of sludge in a turbine lubricating oil composition.

In accordance with this invention, there is provided a rust inhibitor comprising the reaction product of a reactant, selected from the group consisting of an alkenyl succinic acid and an alkenyl succinic anhydride in which the alkenyl radical has from 8 to 18 carbon atoms, and a tertiary amine compound, represented by the formula:

in which R is an aryl or alkaryl radical having from 6 to carbon atoms and R represents a divalent alkylene radical having from 2 to 4 carbon atoms, in a mole ratio ranging from about 1:1 to 2:1 respectively, and at a temperature from about 80 to about 125 C. There is also provided a rust and sludge inhibited turbine lubricating oil composition comprising a major proportion of mineral lubricating oil with conventional additives and a minor amount of the reaction product defined above.

The alkenyl succinic acid and anhydride components employed in making the additive of the invention are represented by the following formulas:

in which R represents an alkenyl radical having from 8 to 18 carbon atoms. Typical alkenyl succinic acids or "ice anhydrides which can be employed are dodecenyl succinic acid and anhydride decenyl succinic acid and anhydride, tetradecenyl succinic acid and anhydride and the like.

The tertiary amine component of the reaction product is represented by the formula:

in which R is an aryl or alkaryl radical having from 6 to 10 carbon atoms and R represents a divalent alkylene radical having from 2 to 4 carbon atoms. The presence of an aryl -or alkaryl radical on the nitrogen atom in the alkanolamine component of the reaction product appears to be essential to the preparation of an effective rustinhibiting and sludge-inhibiting reaction product which does not degrade other desired properties possessed by a turbine lubricating oil. For example, reaction products in which R is an alkyl radical on the nitrogen atom have the undesirable property of degrading water separating characteristics of the turbine oil composition.

Tertiary amine compounds which will form effective rust and sludge inhibiting reaction products include: phenyldiethanolamine, tolyldiethanolamine, isopropylphenyl diethanolamine, ethylphenyl diethanolamine, phenyl dipropanolamine and the like.

The rust inhibiting reaction product of the invention is prepared by reacting the alkenyl succinic acid or anhydride and the above-defined tertiary amine in approximately 1:1 to 2:1 mole ratios respectively. The components of the reaction product are admixed either With or without the aid of a mutual solvent and reacted at a temperature from about to about C. A catalyst, such as p-toluene sulfonic acid can be used to promote reaction.

The following examples illustrate the preparation of the reaction product of the invention.

EXAMPLE I 830 grams (4.58 moles) of N-phenyl diethanolamine were dissolved in 2200 ml. of benzene and heated at reflux temperature for about 2 hrs. to remove the water present in the ethanolamine. 1220 grams (4.58 moles) of dodecenyl succinic anhydride were added to the ben zene solution over 80 minutes while the solution was maintained at a temperature from 188204 F. After all ofthe anhydride had been added, the reaction was continued for about 4 hours at about ZOO-201 F. The benzene was then removed by distillation and by blowing nitrogen through the reaction product. 2063 grams of the reaction product (Additive A) was recovered having a Neutralization No. of 121 as compared to a calculated Neut. No. of 126.

EXAMPLE II 27.4 grams (0.20 mole) of N-phenyl diethanolamine were dissolved in 300 m1. of benzene and heated at reflux temperature to remove water. 106.4 grams (0.40 mole) of dodecenyl succinic anhydride were added to the benzene solution and the mixture reacted at a temperature from 180 to 184 F. for 2 hours. The benzene was removed by distillation and grams of product recovered (Additive B) having a Neutralization No. of as compared to a calculated Neut. No. of 168.

The lubricating oil composition of the invention comprises a refined mineral lubricating oil containing conventional turbine oil additives and from about 0.01 to 5 weight percent of the reaction product of the invention. The preferred concentration of the reaction product in the lubricating oil is from about 0.025 to 0.5 weight percent. The reaction product is readily soluble in mineral lubricating oils and can be readily blended therein to prepare the lubricating composition.

The rust-inhibiting and sludge-inhibiting properties of the reaction product of the invention were determined in the ASTM Oxidation Test (D-943) wherein the oil sample is subject to a temperature of 95 C. in the presence of water, oxygen and an iron-copper catalyst. This test Obviously numerous modifications and variations of the invention may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be made as are indicated in the appended claims.

We claim:

is particularly designed to determine the oxidation char- 5 1. A turbine lubricating oil composition comprising a acteristics of steam-turbine oils. The base blends emmapor proportion of a mineral lubricating oil and a minor ploye in h e tests, Bl n A r gh D, Wer refi rust inhibiting amount of the reaction product of a reactparaffin base mineral oils containing 0.30 weight percent ant selected from the group consisting of an alkenyl sucditertiary butyl cresol, 0.033 weight percent tetrapropenyl cinic acid and an alkenyl succinic anhydride in which the succinic acid, and 6 ppm. silicone polymer, which are alkenyl radical has from 8 to 18 carbon atoms, and a terwidely used in inhibit oxidation, rusting, and foaming, tiary amine reactant represented by the formula: respetively in steam turbine oils. Base Blend E was the same as Base Blend C plus 0.1 weight percent of an 2 alkylated aromatic aimine added as supplemental oxidation in which R 1s an aryl or alkaryl radical having from 6 to inhibitor. These base blends had the following charac- 10 carbon atoms and R is a divalent alkylene radical havteristics. ing from 2 to 4 carbon atoms in a mole ratio ranging from Base Blend A B O D E Gravity, API 30. 0-33.0 20.0-32.0 28.5-31.5 27.0-30.0 23.5-31.5 Flash GOO, F. (min). 300 400 410 60 410 Vis.SUS at 100 F 140-15 200-225 300-315 650-700 300-315 Color ASTM (max.) 1. 0 1.0 1.0 2. 0 1. 0 Pour, F. (max.) 0 5 5 5 5 Neut. No. (man) 0. 10 0. 1o 0. 10 0. 10 0. 10

The Oxidation Test was run until the acidity of the about 1:1 to 2:1 respectively and at a temperature rangoil sample reached a Neutralization No. of 2.0. The ing from about 80 to about 125 C. length of time it took to reach this end point is given in 2. A lubricating oil composition according to claim 1 hours. Likewise, the time to formation of rust on the steel containing from about 0.01 to 5 weight percent of said coils and sludge in the oil is shown in hours. The results reaction product. are the average for two or more test samples. 3. A lubricating oil composition according to claim 1 in which said alkenyl succinic anhydride is dodecenyl ASTM OXIDATION TEST succinic anhydride and said reaction is conducted using Hours a mole ratio of about 1:1.

4. A lubricating oil composition according to claim 1 Base blend Additivewh percent i}? Rust Sludge 40 in 1which said tertiary amine reactant is N-phenyl diethano amine. f: 'gfifgag figg'gj 31$ 532 32 5. A lubricating oil composition according to claim 1 (125 AdtliiiveB 31092 None None containing from about 0.05 to 1 weight percent of diter- 3 3,: I "gififiiffffff i: 3 3; 2 3; tiary butyl cresol and from about 0.01 to 0.15 weight per- D 0.05 Add't' A 2,602 None No e 3 iff 1,720 664 6 cent of tetrapropenyl SUCClIllC acid.

on 0113i 1, E 8 32; 95: References Cited 1, 0 B 2 gig g g UNITED STATES PATENTS n o e oilfg None 27800 3 8 3 2,588,412 3/1952 Rocch n Do 0.03 AdditiveA 3,222 None None 2,604,451 7/1952 Rocchim. Do 0.025 Additive B 2, 940 None None 3 183 070 5/1965 Udelhofem 3,368,971 2/1968 Retzlotf et al. The foregoing test results show that the reaction prodnets of the invention very substantially improved the oxi- DANIEL WYMAN Pnmary Exammer dation resistance of the lubricating oil composition. More surprisingly these anti-rust agents completely arrested the formation of rust and the deposition of sludge in the improved lubricating oils.

W. J. SHINE, Assistant Examiner U.S. Cl. X.R. 252-392, 403 

